AbstractWe examined differences in accuracy during memory-guided positioning movements while participants had their eyes-closed versus eyes-open, but blindfolded. Participants performed target relocations in three conditions; blindfolded with eyes-open, eyes-closed, and eyes-open. Individuals were expected to be more accurate in the eyes-closed versus the blindfolded condition because closing the eyelids creates a neural signal indicating that vision will be unavailable for sensory-guidance. When blindfolded, the system may use the occluded vision which could interfere with feedback-based processes. Sixteen right-hand dominant participants were recruited. Four targets were placed at 10cm or 30cm from a home position at heights of 10cm or 20cm. Participants made 10 relocations of each target under each vision condition. For an attempt, participants found the top of a dowel and returned to the home position. The dowel was removed and participants relocated the target. Participants triggered an optoelectronic recording at the predicted location. Analyses of radial error revealed main effects of Visual Condition, F(2,30)=48.13, p<0.001, Target, F(3,45)=3.73, p<0.018, and a significant interaction of Visual Condition and Target, F(6,90)=4.09, p<0.001. With vision, participants were more accurate than in the occluded conditions and more accurate to shorter rather than taller targets. With eyes-closed, they were more accurate to the farther-tall target compared to the near targets when blindfolded. The results support the notion that the sensory-motor system is more efficient when it knows that vision is unavailable compared to when it attempts to incorporate obstructed vision. The outcome has implications for designing movement rehabilitation techniques for people with adventitious vision loss.
Acknowledgments: Canada Foundation for Innovation